Big Sur - Unlocking with Apple Watch

I just tried signing out and back in with Apple ID. My watch unlocked my MacBook Pro twice, then it stopped working again.

Holy s***. Too many dead brain cells in this exercise, and it still doesn't work. Someone at Cupertino is smoking way too much.

Done this multiple time and it does not work for me. When I disable Keychain sync in iCloud, the checkmark immediately returns.

I've tried many different ways to fix this same problem, but bartlomiej has had the ONLY fix that has worked. THANK YOU!!!

Still won't work with Big Sur 11.1 and a Series 4 watch with watchOS7.2

I fixed problem with Big Sur updating problem but I just updated my MacBook Pro to Big Sur 11.1 then did not unlock again!!

Was all working perfectly for me UNTIL installing 11.1 this morning - now not working at all. FFS apple...

That works for me too, until someone else logs onto the same computer. That breaks the chain and it has been this way ever since I've had my MacBook Pro.

Surprised no one else thought of that. Or maybe that didn’t work for them, so they’re looking for a solution to it not working?

Fantastic, worked like a charm, thank you

All these methods work until a second person logs into the computer. After that, nothing works.

I also have this issue since upgrading to Big Sur. My Apple Watch (series 4, latest iOS) has worked seamlessly with other operating systems but just refuses to connect to my watch.

I've tried all of the suggestions in this thread but to no avail.

Hoping Apple fix this soon as it's a very useful feature.

None of what I've seen on this thread works. Back in old days, there was a quaint custom of *TESTING* software before rolling it out. But I guess that's out of fashion now. Better to just use your customers as guinea pigs.

This was the first thread that popped up when I googled the question, so I'm just gonna paste the response by @Stoska992 from this thread;

I've finally fixed it! I found a bunch of errors related to "AutoUnlock" in the Console that was hinting to me that there was some invalid state on my Mac with keys and plists not being reset properly. 

Steps (follow at your own discretion)

1. Open "Keychain Access"
2. In "View", enable "Show Invisible Items"
3. Search for "Auto Unlock"
4. You should see a whole bunch of application passwords for "Auto Unlock: XXXX's ..."
5. Select all records and delete (this will reset/disable auto unlock on other Macs if you use multiple Macs)
6. Whilst still in "Keychain Access", search for "AutoUnlock" (no space)
7. There should be 4 entries for "tlk" "tlk-nonsync" "classA" "classC"
8. Select 4 records and delete (don't worry if they re-appear, the system repairs this automatically)
9. Open "Finder" and navigate to "~/Library/Sharing/AutoUnlock"
10. There should be two files "ltk.plist" and "pairing-records.plist"
11. Delete both files
12. Open "System Preferences" and try enabling auto unlock. You may need to enable it twice, the first attempt will fail.

My Apple Watch will not unlock my iMac after Big Sur as well. When I went to the Security & Privacy section in settings I saw that the box was checked to "Use you Apple Watch to unlock apps and your Mac". I unlocked the section then unchecked the box but upon trying to recheck the box I get the following Error.

"Your Mac was unable to Communicate with your Apple Watch. " Even though the watch was unlocked, on my wrist, and powered on.